Bait stations are well known and many devices for holding a bait formulation comprising an attractant with a poison to destroy pests, particularly crawling insects, have been disclosed. For example, U.S. Pat. No. 4,485,582 to Morris teaches the use of a feeding station administering a poison housed in a base with a permanently affixed cover. Access to the poison is controlled by three types of openings, one type being formed in the cover, the second type being formed in an extension mounted in the ground, and the third type being formed in a inner compartment.
U.S. Pat. No. 4,837,969 to Demarest discloses a bait station having a multi-lobed structure with ramps. Inner walls intersect a ramped structure forming guides to direct insects to a central well containing a bait. A cover is also permanently attached to a base where apertures allow access to the central well containing the bait.
U.S. Pat. No. 4,894,947 to Brandli discloses an insect feeding station having guide walls leading from openings on the periphery of the station to a central poison area. The guide walls function to guide the insect toward the poison and to prevent departure from the station before contact with the poison. The central poison area can have a contrasting or luminous color under the poison indicating when the poison is consumed.
U.S. Pat. No. 5,033,229 to Demarest et al. teaches a bait station comprising a ramped base with a funneled reservoir for holding a liquid bait-toxicant formulation. The liquid in the reservoir is released onto an absorbent pad in a central well where insects contact through access openings formed in the ramped base.
U.S. Pat. No. 5,548,922 to Wefler discloses another bait station using a liquid insect bait. The bait station includes a hollow body having a base and a ramped cover sealed to the base in a liquid tight fashion. The base has a floor housing a porous disk which functions to transport a liquid insect bait absorbed onto the disk through capillary action to a central stage formed from the ramped cover. Portals in the ramped cover are of a size to at least allow feeding structures of targeted insects access to liquid on the disk beyond the central stage.
Generally similar bait stations are disclosed in U.S. Pat. No. 4,208,829 to Manning; U.S. Pat. No. 4,497,131 to Hicks; U.S. Pat. No. 4,563,836 to Woodruff et al.; U.S. Pat. No. 4,625,452 to Knote; U.S. Pat. No. 4,658,536 to Baker; U.S. Pat. No. 4,841,669 to Demarest et al.; U.S. Pat. No. 5,152,097 to Rhodes; U.S. Pat. No. 5,357,709 to Lin; and; U.S. Pat. No. 5,737,870 to Thind.
One disadvantage to the prior art bait stations is their complexity of design and higher manufacturing costs associated with forming intricate baffles and internal compartments to guide the insect and separate the bait from outside tampering. In addition, past bait stations were designed for selective entry that sought to prevent children from entering and contacting the poison than selective entry between various types of insects. Therefore, beneficial insects to an ecosystem not intended to be targeted were often destroyed with the targeted pests. Moreover, the design of past bait stations did not allow for the selection of the type of insects to be targeted for destruction to be readily changed either by the manufacturer, or by the end user. In addition, due to the complexity of most designs, the insect entry openings to the bait were often limited, thereby reducing the efficacy of the bait station.
Another disadvantage to the prior art bait stations is typically that the bait and poison are permanently fixed in the bait station. Therefore when the bait is exhausted the station is rendered useless and cannot be replenished. Another disadvantage is that once the type of bait is chosen for the station, it often cannot be changed to suit changing insect populations or a change in the environment the station is desired to function in. In addition, past designs of bait stations, particularly those employing liquid baits, typically do not allow ready access to the bait to check the level and/or integrity of the bait. Yet another disadvantage, particularly with liquid baits, is the rate of evaporation or the fact that contact of the bait with the surrounding air and environment are not controlled. Therefore, the effectiveness and amount of bait in the station can be compromised from environmental factors such as heat, sunlight, wind, rain and moisture, or any other factor that will affect the bait.
What is desired, therefore, is a bait station with an economical design, and a plurality of openings that selectively guide targeted insects to a poisonous bait, along with the ability to readily change the bait employed and control the evaporation and effectiveness of the bait within the station.